Method for recycling palladium from silver electrolyte by using dimethylglyoxime

Abstract

The invention discloses a method for recycling palladium from a silver electrolyte by using dimethylglyoxime. The method comprises the following steps: adding dimethylglyoxime into a palladium-containing electrolyte for precipitating palladium; performing solid-liquid separation, returning filtrate as an electrolyte, and eluting filter residue with nitric acid acidification water to obtain a dimethylglyoxime palladium crude product; dissolving the dimethylglyoxime palladium crude product with aqua regia, and then precipitating palladium with ammonium chloride; eluting an obtained ammonium chloropalladate precipitate with an ammonium chloride solution until filtrate is colorless; and adding water, heating, and dissolving; filtering, and cooling filtrate; adding ammonia water, complexing and dissolving; cooling, filtering, and eluting the filter residue with ammonia water; adding hydrochloric acid for acidifying filtrate; filtering to obtain a diammonium dichloropalladite precipitate; and reducing the precipitate by hydrazine hydrate to obtain palladium sponge with the grade of 99.99%. Heating and pH regulation are not required, and only quantitative precipitation of palladium is required; the selectivity is good; and the precipitated dimethylglyoxime palladium can achieve a very high purity after simple eluting, so that the palladium purifying process is greatly shortened and the palladium recycling rate is improved; the using amount of dimethylglyoxime is low; and except a small amount of ethanol, other ions are not brought, so that the reuse of the electrolyte is not affected.

Description

Technical field: [0001] The invention relates to a method for smelting precious metals, in particular to a method for recovering palladium in silver electrolyte by using diacetyl oxime. Background technique: [0002] About 60% of the palladium in the anode in the silver electrolysis process enters the electrolyte. The traditional method of recovering palladium is to use activated carbon adsorption, but there are the following shortcomings: activated carbon needs to be pretreated and regenerated, and the electrolyte needs to be heated to 80-90°C before adsorption; Add sodium hydroxide to adjust the pH to 1.5-1.8, and the accumulated sodium ions will affect the reuse of the electrolyte after palladium precipitation; activated carbon not only adsorbs palladium, but also adsorbs a large amount of silver, bismuth and other metals, with poor selectivity , It also adds difficulty to the subsequent purification of palladium. The second is to use xanthate to precipitate palladium. The di...

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Problems solved by technology

[0002] About 60% of the palladium in the anode in the silver electrolysis process enters the electrolyte. The traditional method for recovering palladium is to use activated carbon to adsorb, but there are the following disadvantages: the activated carbon needs to be pretreated and regenerated, and the electrolyte needs to be heated to 80-90°C before adsorption; Add sodium hydroxide to adjust the pH to 1.5-1.8, and the accumulated sodium ions will affect the reuse of the electrolyte after palladium precipitation; activated carbon not only adsorbs palladium, but also adsorbs a large amount of silver, bismuth and other metals, with poor selectivity , which also increases the difficulty of subsequent purification of palladium

The second is to use xanthate to precipitate palladium. The disadvantages are: before precipitation, the electrolyte needs to be heated to 80-90 ° C, and the pH should be adjusted to 2.0; smelly gas, polluting the environment

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